Among the shutters that are installed in imaging devices, there are focal plane shutters that are provided with a leading blade, a trailing blade, the leading blade driving portion for driving the leading blade, and a trailing blade driving portion for driving the trailing blade. The leading blade driving portion and the trailing blade driving portion are each structured from a first driving member and a second driving member. This focal plane shutter may operate in a normally closed mode or a normally open mode. Here the normally open mode is that wherein the opening is open when in imaging standby wherein, after the leading blade has closed the opening, the leading blade opens the opening, following which the trailing blade operates to close the opening. The normally closed mode is that wherein the opening is closed by the leading blade when in imaging standby mode, and, at the time of imaging, the leading blade opens the opening, following which the trailing blade operates to close the opening. In an exposing operation wherein the leading blade opens the opening and the trailing blade closes the opening, an image of the photographic subject is captured by an imaging element of the imaging device.
For example, in an exposing operation in the focal plane shutter set forth in Japanese Unexamined Patent Application Publication 2015-125298, the leading blade second driving member is rotated clockwise by the biasing force of a leading blade driving spring, to push a leading blade first driving member, which is connected to the leading blade. A leading blade second driving member rotates following the leading blade first driving member, causing the leading blade to move. The leading blade opens the opening thereby. Moreover, after a prescribed time following the start of movement of the leading blade, the trailing blade closes the opening by moving in the same manner as the leading blade.
The focal plane shutter set forth in Japanese Unexamined Patent Application Publication 2015-125298 is provided with a leading blade brake lever for braking the leading blade that is moving during the exposing operation. The leading blade brake lever is biased in the clockwise direction by a spring. The leading blade brake lever makes sliding contact with a driving pin for the leading blade first driving member, to rotate in the counterclockwise direction. The leading blade brake lever is biased in the clockwise direction, and thus can brake the leading blade first driving member, that is, can brake the leading blade that is connected to the leading blade first driving member.
When the focal plane shutter setting forth in Japanese Unexamined Patent Application Publication 2015-125298 operates in the normally closed mode, the leading blade is returned to a position that closes the opening, prior to the leading blade first driving member and the leading blade second driving member starting the exposing operation, and thus the brake lever for the leading blade is rotated in the clockwise direction by the biasing force of the spring. The clockwise rotation of the leading blade brake lever is stopped by the leading blade brake lever contacting a stopper pin. Through this, the leading blade brake lever returns to the position of sliding contact with the driving pin of the leading blade first driving member. Note that the discharging operation is an operation that applies a biasing force to the leading blade driving spring and the trailing blade driving spring for subsequent imaging. Moreover, when the focal plane shutter set forth in Japanese Unexamined Patent Application Publication 2015-125298 operates in the normally open mode, the leading blade first driving member is returned to the position from prior to the beginning of the exposing operation through releasing of the retention of the driving pin of the leading blade first driving member, after the start of imaging, and thus the leading blade brake lever, in the same manner as in the normally closed mode, is returned to the position of sliding contact of with the driving pin of the leading blade first driving member. That is, the leading blade brake lever set forth in Japanese Unexamined Patent Application Publication 2015-125298 is returned to the position for braking the leading blade, linked to the operation of the leading blade first driving member, through the same biasing force as the biasing force for braking the leading blade.